Circuit for controlling sound generator for alarm clocks

ABSTRACT

A transistorized circuit is provided for supplying energy to the electric sound generator of an alarm clock. The transistorized circuit is in the form of an astable multivibrator with a relatively long period so that the sound generator will sound intermittently when supplied with energy by the circuit. The circuit includes a resistor-capacitor timing network to determine the period thereof and an auxiliary resistor is provided which can momentarily be connected in the resistor-capacitor circuit to reduce the charging time of the capacitor.

United States Patent Assmus CIRCUIT FOR CONTROLLING SOUND GENERATOR FOR ALARM CLOCKS [75] Inventor: Friedrich Assmus, Schramberg,

Germany [73] Assignee: Gebruder .lunghans GmbH,

Schramberg, Germany [22] Filed: Dec. 11, 1973 [21] Appl. No.: 423,780

[30] Foreign Application Priority Data Dec. 13, 1972 Germany .1 2260886 [52] US. Cl. 331/108 A, 331/111, 340/384 E [51] Int. Cl. H03k 3/282 [58] Field of Search ..331/111, 108 A, 113; 340/384 E [56] References Cited UNITED STATES PATENTS Bowers 331/108A 3,341,840 9/1967 Berkheiser 331/111 OTHER PUBLICATIONS Popular Electronics, pages 81, 82 July 1968.

Primary Examiner-John Kominski Attorney, Agent, or Firm-Walter Becker [5 7 ABSTRACT A transistorized circuit is provided for supplying energy to the electric sound generator of an alarm clock. The transistorized circuit is in the form of an astable multivibrator with a relatively long period so that the sound generator will sound intermittently when supplied with energy by the circuit. The circuit includes a resistor-capacitor timing network to determine the period thereof and an auxiliary resistor is provided which can momentarily be connected in the resistorcapacitor circuit toreduce the charging time of the capacitor.

13 Claims, 5 Drawing Figures PATENTEL 1E8 I 01974 SHEET 2 OF 3 Pmmm ac I M 3.854.104

' SHEEI 30! 3 Fig. 5

CIRCUIT FOR CONTROLLING SOUND GENERATOR FOR ALARM CLOCKS The present invention relates to a circuit and control means for the fast starting of an astable multivibrator of low sweep frequency for controlling a sound generator for alarm clocks which is arranged in the output circuit.

The high RC-constant of such multivibrators brings about that the alarm clock after insertion of and connection with the battery is not immediately in readiness for setting off an alarm.

In conformity with the magnitude of the RC- constant, a certain time lapses until the multivibrator begins to signal and thus emits alarms through for instance a buzzer. This fact is particularly evident with socalled repeat alarm clocks. In such an instance the dead period considerably exceeds one minute. When the battery has been inserted and connected and the alarm clock can meet its purpose, this time delay or dead period is of no great disadvantage because the condenser has more than ample time to be charged again between the alarm set-off time periods and the switch threshold of the transistor. The multivibratorwill thus be immediately in readiness-for operation for setting off a new alarm'.

For practical reasons, however, all battery operated alarm clocks are dispatched without batteries. This fact, however, may with heretofore known alarm clocks of the type involved have a disadvantageous effect when a sale is to be made. More specifically, if the watchmaker or the salesman wants to demonstrate an alarm clock of the type involved to a customer, the salesman has first to insert a battery into the clock. After the salesman has subsequently released the alarm release time point, first no signal will be emitted because, as mentioned above the condenser of the RC member has first to be charged up.

It will be evident that this drawback may have an embarrassing effect and might jeopardize the sale if the customer is not familiar with the above mentioned time delay caused by the RC member. Thus, the customer might think that the clock is defective and may not buy the same.

It is, therefore, an object of the present invention'to provide a circuit and control means for the quick starting of an astable multivibrator of low sweep frequency for controlling a sound generator in the output circuit for alarm clocks, which will overcome the above outlined drawback. This object and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 illustrates a multivibrator circuit with the control device according to the invention.

FIG. 2 illustrates a first embodiment of a quick action switch arrangement according to the invention.

FIG. 3 represents a second embodiment of a quick action switch arrangement according to the invention.

FIG. 4 shows a multivibrator circuit with a third embodiment of a quick action switch arrangement of the invention.

FIG. 5 illustrates a multivibrator circuit with a fourth embodiment of a quick action switch arrangement in conformity with the present invention.

The circuit according to the present invention is characterized primarily in that the charge resistor of the RC member which determines the signal delay is bridged by a series arrangement comprising a quick action switch and resistor means.

In conformity with the present invention, the quick action switch preferably comprises a current conducting rail in contact with a battery pole or is coupled to the turn-off key.

The quick action switch, however, may also in a particularly advantageous manner comprise alarm tension spring means which serve as alarm release switch means.

The quick action switch and the resistor may be combined to a kind of potentiometer which is preferably manually operable.

The arrangement according to the present invention makes it possible to reduce the dead period of an electronic alarm clock after the insertion of the battery to a minimum, and does so with relatively simple means. The product is thus greatly perfected and improved.

Referring now to the drawings in detail, the multivi brator circuit in all of the FIGURES of the drawing comprises for instance complementarily arranged transistors T1 and T2, electric time members R1, R2 and C which determine the duration of the signals and the intervals therebetween, and a buzzer S in the output circuit. The character Kl designates the alarm release switch, and the character K2 designates the manual switchoff switch.

As indicated in FIG. 1, arranged in parallel to the resistor R1 which determines the intervals is a quick action switch M and a resistor R3. The resistor R3 preferably has a value of approximately 1 kilo-ohm. When actuating the quick action switch M, the time for charging the condenser C can be considerably reduced in view of the time constant determined according to the invention by the replacement resistor R] and R3. The quick action switch can be actuated in different ways and may be of different type.

In conformity with FIG. 2, the quick action switch is formed advantageously by means of the customary current conductor rail 1. The other contact section which is designated with reference numeral 2 is connected to the resistor 3 forming a part of the present invention. The customary current conductor rails which are connected to the poles of the battery are, of course, also connected to the driving circuit for the oscillating system of the clock which, however, is not illustrated.

The current conductor rail 1 is expediently so designed that when the battery is inserted into the clocks, the battery will for a brief period have the edge of part 1a pressed against the contact section 2. This design of contact rail may simultaneously also serve as safety means for the connection of the battery.

FIG. 3 shows a quick action switch M which can be simultaneously actuated by the switch of key 3 of the alarm clock. In the illustrated position, the switch of contacts K2 are closed.

If the key is pressed into the dash line position, these contacts are open. If the key is now pressed briefly further against a spring force acting in the direction of the arrow, the contacts 4 and 5 of the quick action switch M contact each other. In order to assure the operation of the multivibrator it is, of course, necessary that the switch of key 3 is returned to its original position and the alarm release switch K1 is closed.

FIG. 4 illustrates a particularly interesting solution to the problem underlying the present invention.

In this instance the alarm clock release switch K1 which is preferably designed as an alarm tension spring 6 may be combined with the quick action switch M. To this end, spring 6 has two contact areas 6a and 6b and the counter-contacts 7 and 8. When the alarm tension spring engages the alarm release bushing 9 in the direction of the arrow, its contact area 6b briefly contacts the contact area 7 and thus likewise forms a quick action switch M. Subsequently, the alarm release switch is closed by means of the contacts 6a and 8. However, the alarm clock has already previously by the quick action switch 6b/7 been placed into readiness of operation so that also in this instance an alarm signal will immediately be generated.

This embodiment is particularly advantageous as to manufacture and operation.

FIG. illustrates a further possibility of briefly reducing the resistance of the valve resistor R1 and of forming a quick action switch. in this instance this is realized by means of a variable resistor 10. in the illustrated position of operation the resistor 10 has a high value. It can preferably manually be brought into a low ohm position. After each actuation of the switch, a spring 11 sees to it that the switch is returned to its high ohm position.

It is, of course, to be understood that the present invention is, by no means, limited to the specific showing in the drawings but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. In a low frequency multivibrator circuit, especially for driving the sound generator of an alarm clock; a transistor having a base terminal and load terminals in the form of an emitter terminal and a collector terminal, a load having one side connected to one of said load terminals and the other side adapted for connection to one side of a source of direct current voltage, a first switch adapted for clock actuation and a second switch in series therewith adapted for manual actuation, one side of the serially connected switches connected to the other load terminal and the other side thereof adapted for connection to the other side of said source, a first resistor having one end connected to said other side of the serially connected switches, a capacitor having one side connected to said other end of said first resistor, a second resistor connected between the other side of said capacitor and said one load terminal, means operatively connecting the juncture of said first resistor and capacitor with said base terminal so as to bias the transistor to conduction when the capacitor attains a predetermined charge, a third resistor, and third switch means for momentarily connecting said third resistor in parallel with said first resistor to reduce the charging time of said capacitor.

2. A circuit according to claim 1 in which said source is a battery, battery rails between which said battery is adapted to be received with the terminals engaging said rails and one rail connected to said other side of said load and the other rail connected to said other side of said switches, said third resistor having one end connected to one end of said first resistor, said third switch means comprising a further rail connected to the other end of said third resistor and adapted for momentary engagement with the said other battery rail.

3. A circuit according to claim 2 in which said other battery rail momentarily engages said further rail in re sponse to insertion ofa battery between said battery rails.

4. A circuit according to claim 1 which includes an actuator for said second manual switch, said third switch means being operated by said actuator.

5. A circuit according to claim 4 in which said actuator is operable to actuate said third switch means when moved beyond that position in which said second manual switch is opened thereby.

6. A circuit according to claim 1 in which each of said first switch and said third switch means have one element in common, said element being operable for closing said third switch means prior to closing said first switch when said first switch is actuated into closed position by said clock.

7. A circuit according to claim 6 in which said one element is in the form of a spring blade, and a cam driven by the clock and controlling said opening blade.

8. A circuit according to claim 7 in which said spring blade is adapted for communication to said other side of said source.

9. A circuit according to claim I in which said third switch means is in the form of a variable resistor connecting said third resistor in parallel with said first resis tor and having a slider, and means biasing said slider toward maximum resistance position.

10. A circuit according to claim 9 in which said slider is manually moveable toward minimum resistance position and returns to maximum resistance position automatically under the influence of said biasing means.

11. A circuit according to claim I in which said means comprises a further transistor having the base terminal connected to the juncture of said first resistor and capacitor and the load circuit connected between the base of the first mentioned said transistor and the said other side of said load.

12. A circuit according to claim 11 in which the first transistor is a PNP transistor having thecollector connected to said one side of said serially connected switches and the emitter connected to said one side of said load, said source having the plus side connected to the other side of said serially connected switches and the minus side connected to the other side of said load, said further transistor being an NPN transistor having the collector connected to the base of the first transistor and the emitter connected to the minus side of said source.

13. A circuit according to claim 12 in which said load is a sound generator.

* k k l 

1. In a low frequency multivibrator circuit, especially for driving the sound generator of an alarm clock; a transistor having a base terminal and load terminals in the form of an emitter terminal and a collector terminal, a load having one side connected to one of said load terminals and the other side adapted for connection to one side of a source of direct current voltage, a first switch adapted for clock actuation and a second switch in series therewith adapted for manual actuation, one side of the serially connected switches connected to the other load terminal and the other side thereof adapted for connection to the other side of said source, a first resistor having one end connected to said other side of the serially connected switches, a capacitor having one side connected to said other end of said first resistor, a second resistor connected between the other side of said capacitor and said one load terminal, means operatively connecting the juncture of said first resistor and capacitor with said base terminal so as to bias the transistor to conduction when the capacitor attains a predetermined charge, a third resistor, and third switch means for momentarily connecting said third resistor in parallel with said first resistor to reduce the charging time of said capacitor.
 2. A circuit according to claim 1 in which said source is a battery, battery rails between which said battery is adapted to be received with the terminals engaging said rails and one rail connected to said other side of said load and the other rail connected to said other side of said switches, said third resistor having one end connected to one end of said first resistor, said third switch means comprising a further rail connected to the other end of said third resistor and adapted for momentary engagement with the said other battery rail.
 3. A circuit according to claim 2 in which said other battery rail momentarily engages said further rail in response to insertion of a battery between said battery rails.
 4. A circuit according to claim 1 which includes an actuator for said second manual switch, said third switch means being operated by said actuator.
 5. A circuit according to claim 4 in which said actuator is operable to actuate said third switch means when moved beyond that position in which said second manual switch is opened thereby.
 6. A circuit according to claim 1 in which each of said first switch and said third switch means have one element in common, said element being operable for closing said third switch means prior to closing said first switch when said first switch is actuated into closed position by said clock.
 7. A circuit according to claim 6 in which said one element is in thE form of a spring blade, and a cam driven by the clock and controlling said opening blade.
 8. A circuit according to claim 7 in which said spring blade is adapted for communication to said other side of said source.
 9. A circuit according to claim 1 in which said third switch means is in the form of a variable resistor connecting said third resistor in parallel with said first resistor and having a slider, and means biasing said slider toward maximum resistance position.
 10. A circuit according to claim 9 in which said slider is manually moveable toward minimum resistance position and returns to maximum resistance position automatically under the influence of said biasing means.
 11. A circuit according to claim 1 in which said means comprises a further transistor having the base terminal connected to the juncture of said first resistor and capacitor and the load circuit connected between the base of the first mentioned said transistor and the said other side of said load.
 12. A circuit according to claim 11 in which the first transistor is a PNP transistor having the collector connected to said one side of said serially connected switches and the emitter connected to said one side of said load, said source having the plus side connected to the other side of said serially connected switches and the minus side connected to the other side of said load, said further transistor being an NPN transistor having the collector connected to the base of the first transistor and the emitter connected to the minus side of said source.
 13. A circuit according to claim 12 in which said load is a sound generator. 